Ink applicator for gravure printing press

ABSTRACT

An ink applicator for applying ink to the plate cylinder of a gravure press comprising a vessel having an elongated, substantially continuous discharge orifice and adapted to contain ink to a level above the level of the orifice to produce a pressure head and thus afford gravity discharge of ink through the orifice. The vessel is mounted in a position locating the orifice in proximity to the plate cylinder surface so that ink flowing from the orifice contacts and is picked up on the plate cylinder surface. The vessel carries an ink metering or control element, which may be a member constituting one wall of the orifice and positioned to form a clearance gap and control the thickness of the ink coating applied to the cylinder. The vessel is curved generally to conform to the curvature of the cylinder, and its upper end has an opening to admit into the vessel ink removed by the doctor blade, shield members being positioned above the opening to capture and direct the ink into the vessel through the opening. The vessel is kept filled to a given level by ink returned to it through the opening and by a supply conduit receiving makeup ink fed in by the press ink circulation system. Excess ink delivered through the orifice but not applied to the cylinder flows over the upstream wall of the orifice and is returned to the ink reservoir. Adjacent the upstream edge of the orifice is an ink retainer formation adapted to provide an overflow path of substantial width adjacent the cylinder, thereby providing a larger area of contact between the cylinder surface and ink discharged from the vessel through the orifice.

[ 1 Feb. 15,1972

FORElGN PATENTS OR APPLICATIONS [54] INK APPLICATOR FOR GRAVURE PRINTING PRESS 151,673 9/1920 GreatBritain.........................l01/366 [72] Inventor: AliredC.Behringer,Ringwood,NJ.

[73] Assignee: Publication Corporation,

Primary ExaminerJ. Reed Fisher Attomey-Brumbaugh, Graves, Donohue 8; Raymond Greenwich,

Conn.

22 Filed: Apr. 27, 1970 ABSTRACT An ink applicator for applying ink to the plate cylinder of a 211 App]. No.: 32,145

avure press comprising a vessel having an stantially continuous discharge 0 um i o .ummm .m e d In rt k m u w mnmmw m em amg ym 3mm mw wm m m M ia w w em m W m m n sm dr mmmuw n m m w wm w wm mm mmomw w w m; 5 m m m an mwkmm o o in? who wk l m m n c w m m m um a wvmo m mm m m muw e mh 6mm. m w w. o a mm mmr o m.m c m cm w m w m e 1 m 0k wm m w m m m m w im m m w W wm mm w y l u i em w. e mf e d V .l V710 m nn m m 3.0 w oom S 1 l. a m w e Him wwt w mm mm m m fi flwm e i c m .W ct n h M yeo 8 .uu .mmo mwmt cv a ch from the orifice contacts and is picked up on t is curved generally into the vessel through the opening. The vesse y l 77 9 m m wss 3 5 511666 a un WHH%%% e Of m 300/// F 115 211.111 ZM W WWW a H 3, U1 n 4 8 u m mw m S m m m u a 4 a n 0 mm? m m 0 N ""1 M n n. .u u A m m m mmo G P m m m m u S 1.3 S nun m m n P 3, m Wm M WLM "fin f .e l c n n 0 We. A awa t m w a s n r T mmmm m m "0 .m S o ii 0 U "5 8 D PGKBPWPPBR ..0 Hum R M .mm ""hm m 4 0 225533 m m m 1 %44444455 R in n 9999999999 t I 111111111 a m l 73nn332559 l C 2876007 09 w m MWQ 93S7Z73 C1 Ur. J ,A3 2367888 1 .11] 09267 6 3 2 8 6 n walla W. UUr L 5. 1222222 the orifice and is returned to the ink reservoir. Adjacent the upstream edge of the orifice is an ink retainer formation adapted to provide an overflow path of substantial width adjacent the cylinder, thereby providing a larger area of contact between the cylinder surface and ink discharged from the vessel through the orifice.

Ross 802 2/1964 SmejdaW... I23 6/1967 28 Claims, 7 Drawing Figures Smalley INK APPLICATOR FOR GRAVURE PRINTING PRESS BACKGROUND OF THE INVENTION This is a continuation-impart of copending application Ser. No. 704,39 1 filed Feb. 9, i968, and now abandoned.

This invention relates to an ink applicator for applying a coating of ink to the printing surface of a gravure plate cylinder.

in intaglio printing, the printing technique employed in gravure printing presses, a plate cylinder etched with a dot or other form of recessed image is coated with a film of ink and is then wiper by a doctor blade to remove the ink from the cylinder surface but leave ink in the recessed image formation. The usual way of applying an ink coating to the cylinder is to simply immerse the lower portion of the cylinder in an ink tank or fountain which is kept filled by pumping ink into it from an ink supply reservoir. The relatively heavy coating of ink which is picked up onto the cylinder may be reduced to a lesser thickness by a deflector before the final doctoring.

There are a number of problems with the fountain-type inking systems normally used in gravure presses. For one thing, there is a tendency for ink skipping to occur, that is, the formation of streaks on the cylinder surface in which there is no ink. This tendency becomes more and more pronounced as the printing speed is increased, and with the high speeds of modern presses, the problem of skipping has become one of the most serious problems in gravure printing. It appears that the skipping problem is primarily a result of bubbles in the ink that tend to be created as the cylinder surface passes at high speed through the fountain, the bubbles in turn creating air pockets that isolate the ink from the printing surface and prevent pickup.

Another important problem with fountain-type inking systems is that of containing the ink in a confined region so that it does not leak out excessively, such as at the end seals, and build up on the impression roller, bearings and various other vital components of the machine. With a fountain-type inking system, there is a considerable amount of splashing and throwing off of ink, and thus it has been necessary to provide a complex system of seals entirely around the major portion of the plate cylinder. With even the most effective seals a small amount of leakage is almost invariably present, especially at the ends of the cylinder at the points where the doctor blade engages it. Leakage at these points often results in ink pickup onto the impression roller which in turn causes the rubber material on the roller surface to swell, to become overheated and to cause paper breaks. lnk leakage also can result in damage to the printed product by migration of leaked ink onto the paper web.

In addition to theproblem of ink leakage, another aspect of the splashing and throwoff of ink in a fountain-type inking system is the press cleanup which is difficult, time-consuming and costly, both in terms of manpower requirements and shutdown time.

SUMMARY OF THE INVENTION There is provided, in accordance with the invention, a novel and improved ink applicator for applying ink to the plate cylinder of a gravure printing press. More particularly, the applicator comprises a vessel having an elongated, substantially continuous discharge orifice and adapted to contain ink to a level above the level of the orifice, thus providing a head pressure at the orifice and affording gravity discharge of ink through the orifice. The vessel is mounted in a position locating the orifice in proximity to the plate cylinder surface so that ink discharged through the orifice comes into contact with the cylinder surface and is picked up onto it. The vessel carries an ink control element which is preferably a member forming one wall of the orifice, is located in closely spaced relation to the cylinder surface and defines with the cylinder surface a clearance gap controlling the thickness of the ink coating picked up as the cylinder surface moves away from the element. Excess ink discharged through the orifice but not picked up onto the cylinder surface flows over the upstream edge of the orifice and preferably over a formation, such as a flange on the vessel, that is arranged to conduct the overflow ink along a path of substantial width and providing for a substantial area of contact between the ink and the cylinder surface.

The vessel is kept filled to provide the desired head pressure by means of the conventional ink circulating system and also by returning ink wiped from the cylinder surface by the doctor blade directly to the vessel. More particularly, shield elements are disposed in the plate cylinder housing and are so arranged as to guide ink removed from the cylinder surface by the doc tor blade and any ink thrown off the cylinder through an opening in the upper portion of the vessel. This feature of the ink applicator of the invention provides the important advantage of recycling the major portion of the ink initially picked up onto the cylinder surface directly back to the vessel and thus back onto the cylinder surface along the shortest possible path. In conventional gravure presses, ink removed by the doctor blade normally goes back to the storage reservoir and is pumped back into the fountain. Frequently, less pump capacity is needed with the ink applicator of the invention than with conventional fountains.

Makeup ink is supplied to the vessel from a conduit extending into and through it and provided with orifices to distribute ink substantially uniformly along the length of the vessel. Preferably, the orifices are located to direct streams of ink in a direction toward the vessel discharge orifice, thereby providing a velocity head to supplement the static pressure head of ink in the vessel in discharging ink through the orifice.

Alternatively to an ink supply conduit that extends the entire length of the vessel, the ink supply conduit may extend only part way through the vessel and may be open at the discharge end. The conduit is provided with a connection to couple it to an ink supply pipe leading from the ink pump. ink delivered to the supply end of the conduit flows completely through the conduit and is discharged at the opposite, open end, which is preferably formed as a nozzle to propel ink across the remaining length of the vessel in a stream that provides reasonably uniform distribution. The conduit also includes a number of spaced-apart openings for discharging ink into the portion of the vessel occupied by the conduit. It has been found to be desirable to provide at least some of the openings with deflector elements that project into the conduit passage from the downstream edges of the openings and capture and deflect streams of ink out of the conduit into the vessel. This form of conduit, namely one that is open at its discharge end and extends only part way across the vessel, provides the advantages of being readily installed and removed, of being free from possible clogging, inasmuch as ink flows completely through it along its axis, and of being susceptible of being used from either side of the press. The conduit may be arranged to be readily installed and removed by providing a conical seat at the point where the ink supply pipe enters the vessel and by providing a matching flange on the conduit that positions and seals the supply end of the conduit on the seat. At a suitable location along the conduit a releasable connection between the conduit and the vessel that not only secures the conduit to the vessel but also urges the conduit into seated relation on the seat may be provided.

In a preferred embodiment, the applicator is mounted for adjustment of its position to vary the gap between the ink control element and the cylinder surface, such as by pivotably mounting the vessel at a point near its upper end and providing an adjustable holding mechanism to fix the vessel in a predetermined position. The adjusting mechanism preferably includes springs for urging the vessel in a direction to hold the ink control element in a prescribed position adjacent the plate cylinder as established by adjustable stops. An external adjusting device may form a part of the mounting system so that the vessel can be tilted down out of close relation to the cylinder when desired, such as for cleanup. Such a device desirably includes an arrangement for quickly adjusting the applicator for different sized cylinders. The vessel is also preferably provided with one or more outlets at its lowest point to permit ink to drain out when the press is shut down.

It has been found to be advantageous to make the discharge orifice of the vessel with a longitudinal dimension slightly less than the length of the cylinder so that gaps are left between the ends of the cylinder surface and the ends of the orifice. These gaps or hands at the ends of the cylinder, accordingly, do not receive ink directly from the orifice, but the action of the doctor blade as it moves back and forth longitudinally across the cylinder is sufficient to provide a lubricating film of ink in the nonprinting, end portions of the cylinder. This feature is of considerable advantage, inasmuch as it tends to reduce or substantially eliminate end leakage problems.

The ink applicator of the invention ofiers a number of significant advantages, an especially important one being the complete elimination of skipping which, as mentioned above, is a considerable problem in fountain-type inking systems. It also eliminates most of the troublesome splashing and throwing of ink in the inking chamber, which, in conjunction with the reduction of end leakage, contributes to a significant reduction in leakage problems and makes it easier to provide effective seals in the inking chamber. Moreover, the time and labor required for cleanup is significantly reduced. The ink applicator can be built and installed, and in fact can be adapted to many conventional presses having fountain-type systems, at a relatively low cost. Further cost advantages result from reduced shutdown time and lower labor costs involved with cleanup as well as with setting up for a new press run. In this regard, the applicator can be built to be installed in a press in such a way that is can be quickly and easily removed and replaced by another spare applicator unit, thus making it possible to set up the press for a new run by merely removing one ink applicator and replacing it with another. This procedure takes less time than the cleanup of a fountain, which is of particular advantage in the packaging printing industry. Another aspect of the lower cost of the applicator involves the ink pump; in particular, the recycling of most of the ink directly from the doctor blade back to vessel, as described above, in some instances makes it unnecessary to provide as high a pump capacity as might otherwise be required with a conventional fountain.

The adjustable mounting of the vessel makes it possible to use the same inking system with various sizes of plate cylinders and thus adapts the applicator for use in a press of the type described and illustrated in my prior patent U.S. Pat. No. 3,333,535, which relates, inter alia, to a doctor blade mechanism and seal system that can be adjusted for use with various sized plate cylinders.

DESCRIPTION OF THE DRAWINGS For a better understanding of the invention, reference may be made to the following description of exemplary embodiments, taken in conjunction with the FIGS. of the accompanying drawings, in which:

FIG. 1 is an end sectional view of the embodiment in place in a press printing unit;

FIG. 2 is a pictorial view of the ink applicator shown in FIG. I, the cylinder being shown in phantom, the press end frame members being broken away, and a center section of the applicator being broken out;

FIG. 3 is a detail view showing the ink supply conduit serving the applicator vessel, the view being in section taken generally along a plane defined by the lines 3-3 of FIG. 2 and in the direction of the arrows;

FIG. 4 is an end sectional view of another embodiment of the ink applicator;

FIG. 5 is a fragmentary, side-sectional view, on a larger scale, of an upper comer of the vessel of the applicator of FIG. 4, the section being taken generally along a plane represented by the lines 5-5 of FIG. 4 and in the direction of the arrows;

FIG. 6 is a bottom view in section, on the same scale as FIG. 5, of an upper corner of the vessel of FIGS. 4 and 5, the view being taken generally along a plane represented by the lines 6-6 of FIG. 4 and in the direction of the arrows; and

FIG. 7 is a pictorial view, on a larger scale, of a deflector element utilized in the ink supply conduit of the embodiment of FIGS. 4 to 6.

DESCRIPTION OF EXEMPLARY EMBODIMENT The press printing unit shown in the drawings and into which the embodiment of the ink applicator is incorporated is similar in many respects to the press unit described and shown in the specification and drawings of my prior U.S. Pat. No. 3,333,535, and reference may be made to that patent for a full description of the printing unit per se including the doctor blade, the doctor blade mounting mechanism and the ink chamber. It is to be clearly understood, however, that the ink applicator of the invention can be employed in gravure presses having a wide variety of specific designs.

The press includes spaced-apart, vertically disposed end frame members 10 and 12 which carry a plate cylinder 14 and an impression roll 16. The shafts 15 at the ends of plate cylinder 14 are mounted in bearings (not shown) in the end frame members in a manner such that removal and replacement of the cylinders can be accomplished quickly and conveniently. No particular plate cylinder mounting arrangement is shown or described herein, because suitable arrangements are well known to those skilled in the art. The impression roll 16 is journaled in bearings (not shown) carried by an adjustable mounting bracket (not shown) so that the impression roll can be moved relative to the plate cylinder in order to be properly set to the plate cylinder and to accommodate to plate cylinders of different sizes. The plate cylinder is rotated counterclockwise and the impression roll clockwise, as viewed in FIG. 1, and together the cylinder 14 and roll 16 form a printing coupled through which a web 19 to be printed is conveyed by apparatus (not shown) of any suitable design.

The ink to be transferred from the plate cylinder to the paper web is applied to the surface of the cylinder and then removed to leave ink only in the etched images thereon by the ink applicator of the invention, which is described below. The applicator and the major portion of the plate cylinder are contained in a closed ink-confining chamber defined (in part) by the end frame members 10 and 12, by a front cover plate 20, which extends entirely across the front of the press and is hinged to the upper end of a vertical housing plate 22, by a screen 24 carried on angle supports 26 and 28, and by a vertical rear housing plate 30. The space below the screen 24 constitutes a storage reservoir 32 for the ink and is open to the ink-confining chamber through the screen.

The ink-confining chamber further includes a transverse ink deflector plate 36 mounted above the vertical rear wall plate 30, the deflector plate 36 overlapping and spaced from the upper edge of the vertical plate 30. The deflector plate 36 includes flanges 38 at opposite ends which are attached to the end frame members 12 and 14 of the press to secure the plate 36 in the press and is also attached to fixed vertical brackets (not shown). Behind and spaced from the plate 36, with respect to the plate cylinder 14, is a drip guard 40 which is also secured to the fixed vertical brackets and curves rearwardly at its upper end.

The upper portion of the ink-confining chamber is defined by transverse strip 42 which is secured to the upper end of the front cover plate 20 by an angle 44 and engages curved end covers 46 which are fastened on the inside of each of the end frame members 10 and 12. The upper edge of the rear deflector plate 36 is engaged by a flexible seal strip 47 carried by a doctor blade holder 48. Additionally, the ink-confining chamber is defined by the doctor blade 50 and by an end seal structure (not shown) which coacts with the doctor blade to seal the spaces between the ends of the cylinder and the end frames in the region of the doctor blade.

The doctorblade holder 48 is carried by a mounting assembly 52, which is only partially shown in FIG. 1 and is not shown in FIG. 2. A detailed description of the mounting assembly 52 may be found in my above-mentioned prior patent. Suffice it may here that the mounting assembly 52 affords throw-in and throwout of the doctor blade into and out of engagement with the plate cylinder and also affords proper setting of the blade to the cylinder. It also accommodates to various sizes of plate cylinders. It is arranged to be reciprocated back and forth longitudinally along the cylinder correspondingly to reciprocate the doctor blade back and forth across thecylinder.

The ink applicator, which is designated generally by the reference numeral 60, is mounted in the ink-confining chamber generally adjacent the lower rear quadrant of the plate cylinder 14. The applicator 60 includes a vessel 62 having upper and lower walls 64 and 66, respectively, the walls 64 and 66being curved generally to conform to the curvature of the cylinder 14. The vessel further includes end wall members 68 and 70 and an upper tray formation 72 appropriately fastened to inturned flanges on the upper ends of the walls 64 and 66.The uppermost end of the vessel 62 has an opening 74 which extends substantially the entire length of the vessel and is covered by a screen 76.

The upper wall- 64 of the vessel 62 is bent over at its lower end to form a downwardly extending flange 64a, in back of which are installed a reinforcing strip 78 and a series of spaced-apart reinforcing angle members 80. The lower wall 66 is bent around in an upward direction to provide an end portion 66a, the portion 660 being bent back double to provide strengthening. The upper end of the end portion 66a of the wall 66 and the corner of the flanges 64a on the wall 64 are spaced-apart to provide a discharge opening in the vessel. A series of spaced-apart reinforcing plates 81 are installed across the opening, and each of the plates 81 has a cutout 82 in its lower portion to afford communication between the sections at the lower end of the vessel that would otherwise be blocked off by the plates8l. One or more drain openings 83 are provided in the lowest point in the vessel lower wall to allow ink in the vessel to drain out whenever the press is shut down.

lnstalled at the lower end of the vessel 62 are members that coact to define an elongated, narrow, longitudinally extending, continuous discharge orifice 84 that communicates with the outlet opening 79, the members including an angle-shaped member 86-constituting the downstream wall of the orifice 84 and a plate 88 constituting the upstream wall, relative to the direction of rotation of the cylinder 14. The upstanding leg 86a of the member 86 also serves as an ink control element, as described below. Extending forwardly from the plate 88 and bolted to it, is an angle-shaped element 90 that serves as an overflow guide, also as described below in more detail. The length of the orifice 84 is somewhat less, say 2 inches, than the length of the cylinder, thus leaving gaps (A in FIG. 2) at each end of the cylinder to which no ink is applied. As mentioned above, this feature markedly reduces end leakage of ink. Nonetheless the reciprocating movement of the doctor blade draws enough ink into the gaps A so that a lubricating film is provided. The gaps A are, of course, in the nonprinting areas of the cylinden Thevessel 62 is kept filled with ink to a predetermined level above the discharge orifice 84, preferably a level near the uppen'nost end of the vessel, by pumping ink using an appropriate pump (not shown) from an ink supply, such as the reservoir 32, through a pipe 91 which extends through the frame member and-is telescopically received within a pipe section 92 that-is mounted for rotation in the frame member 10 and in turn serves to mount the vessel 62 in the ink-confining chamber for pivotal movement to adjust the position of the orifice 84 and ink control element 86 relative to the cylinder surface. At the inner end of the pipe 92 is a flangedcoupling 94 by which the pipe 92 is connected to a pipe section 96, also flanged, such as by bolts 98, which extends through the vessel 62. Mounted on the outer end of the pipe section 92 is a lever by which the pipe sections 92 and 96 can be manually rotated. The pipe section 92 and the supply pipe 91 are appropriately sealed, such as by O-ring seals (not shown).

Telescopically received in the opposite end of the pipe 96 is a bar element l04'which is flanged and bolted by bolts 106 to the frame member 12, an O-ring or other suitable seal being provided between the pipe 92 and bar 104. The bar 104 extends into the pipe 102 to a point just inside the vessel (see FIG. 3) and constitutes a dead end plug for the pipe as well as a pivot mounting for the other end of the vessel. O-ring seals or the'like (not shown) seal the pipe to the bar. It will be understood by those skilled in the art that different forms of pivot mountings can be used; nonetheless, the use of the supply pipe as a pivot facilitates leading in the pipe while affording adjustment of the applicator without a flexible ink supply conduit.

Ink pumped from the ink supply 32 through the pipe 91 flows into the pipes 92 and 96 and is conducted into the vessel 62 through a series of orifices 1080, 108b, 1086, etc., (FIG'. 3),

' the orifices being of increasing size moving away from the inlet end of thepipe 96 so as to provide substantially uniform distribution of the ink outflow from the pipe 96 into the vessel 62. The orificesl08 are located in the downwardly and forwardly facing sideof the pipe 96 (see FIG. 1) so that the ink discharged through them is directed downwardly and forwardly toward the discharge orifice 84 of the vessel 62. Accordingly, the velocity head of the ink coming from the ink supply pipe 96 supplements the gravity forces by which ink is delivered through thedischarge orifice 84 and applied onto the printing surface of the plate cylinder.

The lower, forward end of the vessel 62 is urged about the pivot mounting constituted by the pipe 92 in a direction toward the plate cylinder by springs 110 coupled between bars 1 12 extending outwardly fromeach end of the vessel and bars 114 extending in from the press end frame members 10 and 12. Also, a spring 116 is coupled between the lever 100 and a pin 118 extending outwardly from the frame member 10. The extent of pivotal movement of the vessel 62 at the urging of the springs 110 and 116 is, however, limited by adjustable stop screws 120 carried by the frame members 10 and 12 and a further adjustable stop screw 122 on the frame member 10 and locatedto engage the lever 100. By appropriate adjustment of the stop screws 120 and 122, the gap between the wiper element 86 on the vessel 62 and the surface of the cylinder can be adjusted to a desired value.

Each of the coacting stops and springs described in the preceding paragraph may be used without the other, and indeed both are shown in the drawing as merely examples of two different forms, each of which may be used alone. Those skilled in the art can readily provide other suitableadjusting and positioning arrangements. Where the press has provision for different cylinder sizes, it is preferable to use an adjusting system for the vessel which operates from outside the ink-confining chamber, and preferably outside the frame, and includes features providing quick setting and adjustment for different cylinder sizes. Such a device will generally embody multiple stops, one for each cylinder size.

in operation, ink contained to a predetermined level in the vessel 62 flows by gravity forces, supplemented by the velocity head of the incoming ink emerging through the orifices 108 in the pipe 96 pumped from the ink supply 32, flows out through the discharge orifice 84 and into contact with the surface of the plate cylinder 14. The ink control element 86 controls the amount of ink picked up onto the cylinder surface in accordance with the setting of the gap between it and the cylinder surface by the set screws 120 and 122. In the meantime, ink which is not picked up onto the cylinder but is discharged through the orifice 84 flows forwardly in a direction against the direction of rotation of the cylinder and over the overflow guide 90. The guide 90 provides a flow path of substantial width along which the ink must flow before it drops downwardly, thereby providing a relatively large area of contact between the ink and the cylinder surface to ensure that adequate ink pickup by the cylinder is obtained. The excess ink flows over the edge of the plate 90 and is returned through the screen 24 back to the reservoir 32 below the screen.

Upon rotation of the plate cylinder, the ink picked up onto its surface is doctored by the doctor blade 50. The ink removed from the cylinder accumulates behind the doctor blade and ultimately is back-pumped or splashed rearwardly by the action of the rotating cylinder toward the seal strip 37 and deflector plate 36, these elements serving to capture the ink removed from the cylinder surface and enable it to flow downwardly along the deflector plate 36 and back into the vessel 62 through the upper opening 74. Inasmuch as the doctor blade 50 removes the major portion of the ink picked up onto the plate cylinder, this recycling feature provides the important advantage of affording the most direct path possible from the blade back to the ink applicator and thus permits the use of a supply pump of relatively low capacity, as compared to that required in a fountain-type inking system.

When the press is shut down at the end of a run or for any other reason, the ink in the vessel 62 flows out through the drain openings 83 at the lowest point in the vessel 62 and thence into the reservoir through the screen 24. Thus, the vessel 62 isautomatically emptied whenever the press is shut down.

FIGS. 4 to 7 illustrate a modified form of ink applicator. The embodiment shown there is, however, basically the same in overall configuration, and operates in essentially the same manner, as the embodiment of FIGS. 1 to 3. Consequently, for the most part the same reference numerals, but in a 100 series, are applied to FIGS. 4 to 6 as are applied to corresponding elements of the embodiments of FIGS. 1 to 3. The view of FIG. 4 may be compared with the view of FIG. 1, and it will be noted that FIG. 4 illustrates portions of the plate cylinder 14, the doctor blade mounting 52, the rear housing plate 30, the transverse ink deflector plate 36 and the flexible seal strip 47, but omits several other components shown in FIG. 1.

In the embodiment of FIGS. 4 to 6, the ink applicator vessel 162 comprises upper and lower walls 164 and 166, respectively, that are of generally the same configuration as those of the embodiment of FIGS. 1 to 3 except that they are curved or bent more sharply in order to provide additional space between the surface of the plate cylinder 14 and the wall 164. In addition, the upper wall 164 is bent upwardly at the left end, relative to FIG. 4, and the edge of upwardly bent portion, which is designated by the reference numeral 1860, constitutes one edge of the elongated orifice 184 through which ink is applied to the cylinder. The edge 186a also serves as an ink control element and is ground to a very close tolerance so that it may be set to the cylinder 14 and provide a metering function, in that it controls the amount of ink applied to the cylinder surface, as described above. Thus, the edge 186a of the upper wall member 164 corresponds to the angle member 86 of the embodiment of FIGS. 1 to 3. The upper wall 164 of the vessel is also reinforced at the portion to the lower left (as shown) where it turns upwardly towards the cylinder by a reinforcing angle element 200.

The lower wall 166 of the vessel 162 is fabricated in two pieces, a first piece 162a extending along the bottom. and up wardly along the rear or right side (relative to FIG. 4) and a section l62b that extends from the lower edge of the section 162a upwardly toward the cylinder. The section l62b is preferably constructed of heavier gauge material and carries a number of spaced-apart, outwardly extending ribs 202 along its outer surface. The lower end of each rib 202 is formed with a semicircular hole 204 that is received by a pin 206 projecting from a lug 208 secured to the main section 166a. A reinforcing angle 208 extends longitudinally along the lower end of the section 166a.

The upper and lower wall members 164 and 166a of the vessel 162 are secured to each other at intervals along the length of the vessel by a series of spaced-apart spacers 210 and at their ends by end members 168. Spacers 212 also spaced along the length of the vessel serve to attach the section 1661) of the lower wall member 166 to the upwardly turned, lower end portion of the upper wall 164. The screws 214 by which the section 166b is secured to the spacers 212 may be readily removed, thereby allowing the section 166!) to be pivoted about the pins 204, thereby opening up the lower end of the vessel for cleaning. Like the embodiment of FIGS. 1 to 3, the embodiment of FIGS. 4 to 6 also includes an angle member mounted close to the upper edge of the wall section 166k.

In essence then, the embodiment of FIGS. 4 to 6 includes, at the orifice end of the vessel, a number of structural modifications that contribute to the simplicity of fabrication, the rigidity of the orifice structure, which in turn affects the accuracy with which an ink coating of predetermined thickness may be applied to the cylinder, and the convenience of cleaning out the vessel. The basic construction and mode of operation of the orifice structure of the vessel are, however, the same as in the embodiment of FIGS. 1 to 3. In this regard it should be emphasized that the edge 186a of the upper wall member 164 provides for the application of a coating of ink to the cylinder of controlled thickness, and the upper edge of the section 166b and the angle member 190 provide an overflow for excess ink and a region in which a quantity of ink is trapped. The ink buildup in this region serves as a barrier against the admission of air into the inking zone and the possible entrapment of air in the ink layer which can result in streaking in the printing. Consequently, the applicator, according to the invention, ensures against streaking and skipping that have been increasing problems in the industry as the speeds of press operation are increased. Printing speeds of over 100,000 linear feet perhour have been run with the applicator of the invention, without any difficulty in the inking system.

The ink applicator of FIGS. 4 to 6 also includes a modified ink supply conduit 196. Whereas in the embodiment of FIGS. 1 to 3 the supply conduit extends entirely across the top of the vessel, the conduit 196 in the embodiment of FIGS. 4 to 6 extends only part way across. It has been found that an ink supply conduit 196 extending approximately one-third the length of the vessel from one of the end walls is appropriate. Referring particularly to FIGS. 4 and 6, the conduit 196 is generally circular in cross section at its supply end (to the left in FIGS. 5 and 6) and is then tapered gradually moving from left to right (with reference to the view in the drawings) so that the discharge end (to the right) is generally oval shaped. The cross-sectional area of the conduit may be generally uniform across its length, thus facilitating the fabrication of the conduit from pipe stock of suitable size.

The shaping of the conduit in the manner described above is primarily for the purposes of providing a nozzle 216 at the discharge end and of reducing the projected area of the conduit in a horizontal plane so that there is a minimum of obstruction to the flow of ink back to the vessel from the doctor blade. The nozzle 216 is of generally oval cross section and lies in a plane that is oblique to the axis of the conduit. This form of nozzle provides a stream or curtain of ink that is narrow in a direction transverse to the longer dimension of the vessel and is directed generally longitudinally but slightly downwardly along the length of the vessel. Thus, the nozzle formation directs a stream of ink generally longitudinally along the upper part of the vessel so that the ink is distributed over the remaining two-thirds of the length of the vessel in a generally uniform manner.

Ink is released from the conduit into the portion of the vessel directly below it through a series of spaced-apart openings 218 in the lower part of the conduit wall. Inasmuch as the velocity of the ink coming through the conduit tends to carry it out through the nozzle 216, it is preferable to provide at least some of the openings 218 with deflector elements 220. An appropriate form of deflector 220, shown in detail in FIG. 7, includes a generally domelike body portion 222 and a plate or flange portion 224 that is formed with a hole 226. The dome or body portion 222 extends into the conduit passage, the element being inserted into an oversize hole in the conduit from the outside, and the flange 224 is secured to the conduit wall. As is readily apparent, the deflector elements are mounted in the conduit with the domelike portions extending from generally the downstream edge of the hole so that the cavity in the dome portion faces toward the stream of ink flowing through the conduit. The dome portion captures a portion of the flow of the ink and deflects it down through the hole and out into the portion of the vessel below the conduit. The spacing and sizes of the holes may be readily determined by those skilled in the art, and it is quite apparent that the sizes, spacings and the presence or absence of deflector elements may be varied to suit the operating conditions of a given installation.

The conduit 220 is mounted in the vessel by merely seating the inlet or supply end in a conical seat element 228 mounted inside one end wall of the vessel concentric with a supply pipe 230. As in the embodiment of FIGS. 1 to 3, the supply pipe 230 may also serve to mount the entire vessel in the press. Advantageously, supply pipes 230 and seats 228 may be mounted in both ends of the vessel so that the apparatus may be readily adapted for use with any press, regardless of which end of the press is equipped with the ink supply system. The supply pipe 230 on the end of the vessel opposite from the end to which ink is supplied from the press inking system may be simply blanked off by installing a suitable plug (not shown).

The supply end of the conduit 196 is provided with a conical or flared flange 232 that matches the conical seat 228, thus providing both a physical connection and a seal between the supply pipe 230 and the supply end of the conduit. A mounting plate 234 is secured to the upper wall of the conduit at an appropriate position and a transverse mounting bar 236 is installed across the top opening of the vessel. The plate 234 has a tapped hole that receives a screw 238 inserted through an elongated hole in the plate 236, and the respective plates 234 and 236 are provided with companion inclined surfaces 240 that urge the conduit 196 to the left, relative to FIGS. 5 and 6, when the plate 234 is pulled by the screw 238 upwardly toward the plate 236. In other words the companion surfaces 240 provide a wedging action that urges the conduit 196 toward the seat 228. Thus, the conduit is mounted in the vessel by only a single screw and can readily and quickly be removed for cleaning.

As in the embodiment of FIGS. 1 to 3, the vessel in FIGS. 4 to 6 is substantially entirely open at its upper end and receives ink thrown off the cylinder and removed by the doctor blade which, in turn, is deflected by the elements 47 and 36 directly back into the vessel, all as described above. A further modification of the embodiment of FIGS. 1 to 3 involves the substitution for the screen 76 located in the top opening of the vessel of a screen 242 that is hinged to the deflector plate 36 at its upper edge and slopes down over the top of the vessel. An outwardly projecting strip 244 suitably secured near the lower edge of screen and extending the entire length of the screen captures ink that tends to flow down the screen and directs it into the vessel. This form of screen provides for more convenient access to the upper end of the vessel and is equally effective in preventing intrusion of pieces of paper and other foreign materials into the vessel.

Thus, there is provided, in accordance with the invention, a novel and improved ink applicator which combines numerous advantages including significantly improved operation, markedly improved printing, especially by reason of eliminating ink skipping, lends itself readily to adjustment for different sized cylinders, reduces the problems of ink leakage by sharply limiting the amount of splashing and ink throwoff in the ink-confining chamber, and provides economic advantages both as to capital cost of construction and installation and as to operating costs of cleanup, changeover and maintenance.

The above-described embodiment of the invention is meant to be merely exemplary, and those skilled in the art will be able to make numerous variations and modifications of it without departing from the spirit and scope of the invention.

All such variations and modifications are intended to be included within the scope of the invention as defined in the appended claims.

I claim:

I. An ink applicator for applying ink to the plate cylinder of a gravure press or the like, the press including a doctor blade to wipe ink from the plate cylinder and leave ink only in a recessed image formed thereon, comprising a vessel defined by spaced upper and lower walls curved generally to conform to the curvature of the cylinder surfaces and of a length such as to extend substantially coextensively lengthwise of the cylinder, the vessel occupying a position generally opposite a lower quadrant of the cylinder surface, means defining an elongated substantially continuous discharge orifice in the vessel, the vessel being formed and oriented to contain ink to a level substantially above the level of the orifice to produce a pressure head at the orifice and afford essentially gravity discharge of ink through the orifice, means mounting the vessel in a position locating the orifice in proximity to the plate cylinder periphery for application to the cylinder surface of the ink discharged through the orifice, and means for supplying ink to the vessel to maintain the pressure head therein as ink is discharged through the orifice and applied to the cylinder.

2. An ink applicator according to claim 1 further comprising ink control means on the vessel downstream from the orifice, relative to the direction of rotation of the cylinder, and including an element spaced from the cylinder surface to define a clearance gap for controlling the thickness of the ink coating picked up on the cylinder surface.

3. An applicator according to claim 2 wherein the vessel orifice is defined by elongated closely spaced parallel members on the vessel, the downstream member, relative to the direction of rotation of the cylinder, constituting the said ink control means.

4. An applicator according to claim 1 further comprising a member on the vessel defining a surface upstream of the orifice, relative to the direction of rotation of the cylinder, and in proximity to the cylinder surface and supporting a band of ink of substantial width in contact with the cylinder surface.

5. An ink applicator according to claim 4 wherein the end of the surface-defining member remote from the orifice defines a clearance gap with the cylinder surface over which ink discharged from the orifice in an amount in excess of the amount picked up on the cylinder overflows.

6. An ink applicator according to claim 1 wherein the mounting means includes pivot members on the vessel pivotably carried by frame elements on the press.

7. An ink applicator according to claim 6 further comprising spring means associated with the vessel for pivoting the vessel in a direction about the pivot mounting to urge the vessel orifice toward the cylinder surface and adjustable stop means for resisting pivotal movement of the vessel at the urging of the spring means and positioning the vessel with the orifice located in predetermined spaced relation to the cylinder surface.

8. An ink applicator according to claim 7 further comprising an operating lever located externally of a frame of the press and coupled to the vessel to afford pivotal movement of the vessel in a direction against the urging of the spring means.

9. An ink applicator according to claim I wherein the ink supply mounting means affords setting the ink supply in adjusted positions relative to any of a plurality of different sized plate cylinders.

10. An ink applicator according to claim I wherein the ink supply means includes a conduit extending through the vessel and having a plurality of outlet openings therein communicating the conduit with the vessel.

11. An ink applicator according to claim 10 wherein the conduit is located in the region of the ink level in the vessel, and the openings are located in the conduit in positions to direct ink generally toward the discharge orifice to provide a velocity head supplementing the static head for discharging ink through the vessel orifice.

12. An ink applicator according to claim '7 wherein the ink supply means includes a conduit extending entirely through the vessel and having plurality of spaced openings communicating the conduit with the vessel, the conduit including portions extending longitudinally from the vessel and pivotably coupled to frame elements of the press, the extension portions of the conduit being the pivot members by which the vessel is mounted on the press frame.

13. An ink applicator according to claim 1 wherein the ink supply means includes an elongated ink supply conduit, the conduit being of a length substantially less than the length of the vessel and having a multiplicity of spaced-apart openings along its length for discharging ink into the vessel and being open at both ends to receive ink at one end and discharge ink into the vessel at the other end, and means coupled to the said one end to supply ink under pressure to the supply conduit.

14. An ink applicator according to claim 13 wherein the said discharge end of the conduit is a nozzle.

15. An ink applicator according to claim 13 wherein at least some of the openings in the conduit have deflector elements projecting into the conduit passage from generally the downstream edges of the openings, relative to the direction of flow of ink through the conduit, whereby ink flowing through the conduit impinges on the deflector element and is deflected thereby out through the associated opening into the vessel.

16. An ink applicator according to claim 13 wherein the means for connecting the conduit to the ink supply includes a conical seat mounted on the vessel, 21 flared flange on the conduit matching the conical seat and means at a location spaced from the supply end of the conduit for securing the conduit to the vessel and for urging the flange of the conduit into seated and sealed relation on the seat.

17. An ink applicator according to claim 16 wherein the means for securing the conduit to the vessel includes members having coacting angularly-related surfaces that provide a wedging action to urge the conduit into seated and sealed relation on the seat.

18. An ink applicator according to claim 1 wherein the lower wall includes first and second sections, the second section being disposed adjacent the orifice and extending substantially the entire length of the vessel, and means reasonably connecting the second section to the first section, whereby the second section may be readily removed for cleaning out the vessel.

19. An ink applicator according to claim 18 wherein the second section of the lower wall is hinged to the first section.

20. An ink applicator according to claim 1 wherein the vessel has a portion at a level below the orifice and constituting the lowest portion of the vessel, and further comprising at least one drain port in the said lowest portion through which the ink in the vessel may drain out upon press shutdown.

21. An ink applicator according to claim 1 wherein the vessel further includes an opening above the ink level and generally at the uppermost ends of the upper and lower vessel walls, and further comprising ink capturing means for capturing ink expelled from the cylinder surface after ink application from the orifice and conducting it into the vessel through the opening.

22. An ink applicator according to claim 1 wherein the vessel further includes an opening above the level of ink, and

further comprising ink capturing means for capturing ink expelled from the cylinder surface after ink application from the orifice and conducting it into the vessel through the opening.

23. An ink applicator according to claim 1 wherein the vessel orifice has a longitudinal dimension less than the longitudinal dimension of the cylinder surface, the vessel being positioned such that the ends of the orifice are spaced inwardly from the ends of the cylinder to leave marginal bands at the ends of the cylinder surface to which no ink is directly applied from the orifice, thereby to reduce ink leakage from the ends of the cylinder surface.

24. An ink applicator for applying ink to the plate cylinder of a gravure press or the like, the press including a doctor blade to wipe ink from the cylinder surface and leave ink only in a recessed image formed thereon, comprising a vessel including spaced upper and lower walls curved generally to conform to the curvature of the cylinder surface and of a length such as to extend substantially coextensively lengthwise of the cylinder, the vessel occupying a space adjacent generally a lower quadrant of the cylinder, means defining an elongated substantially continuous outlet orifice adjacent generally the lowermost end of the vessel and facing upwardly in proximity to the cylinder surface, the vessel being adapted to contain ink to a level substantially above the level of the orifice thereby to produce a pressure head at the orifice and afford gravity discharge of ink through the orifice, means defining an opening in the vessel above the ink level, an ink control element on the vessel downstream of the discharge orifice, relative to the direction of rotation of the cylinder, and in closely spaced relation to the cylinder surface and defining a clearance gap controlling the thickness of the ink coating applied to the cylinder, means for supplying ink to the vessel to maintain the pressure head therein as ink is discharged through the orifice and applied to the cylinder, and means for mounting the vessel in a position adjustably locating the ink control element in predetermined spaced relation from the cylinder periphery for application to the cylinder surface of an ink coating of predetermined thickness.

25. An applicator according to claim 24 further comprising a member on the vessel defining a surface upstream of the orifice, relative to the direction of rotation of the vessel, in proximity to the cylinder surface for supporting a band of ink discharging from the orifice of substantial width in contact with the cylinder surface.

26. An ink applicator according to claim 25 wherein the end of the surface-defining member remote from the orifice defines a clearance gap with the cylinder surface over which ink discharged from the orifice in an amount in excess of the amount picked up on the cylinder overflows.

27. An ink applicator according to claim 24 wherein the ink supply includes a conduit extending through the vessel and having a plurality of openings communicating it with the vessel, the openings located on the conduit in positions to direct ink in a direction generally toward the vessel orifice.

28. An applicator according to claim 24 wherein the orifice has a longitudinal dimension less than the longitudinal dimension of the cylinder surface, the vessel being positioned so that the ends of the orifice are spaced from the ends of the cylinder surface to leave marginal bands on the ends of the cylinder surface to which no ink is directly applied from the orifice. 

1. An ink applicator for applying ink to the plate cylinder of a gravure press or the like, the press including a doctor blade to wipe ink from the plate cylinder and leave ink only in a recessed image formed thereon, comprising a vessel defined by spaced upper and lower walls curved generally to conform to the curvature of the cylinder surfaces and of a length such as to extend substantially coextensively lengthwise of the cylinder, the vessel occupying a position generally opposite a lower quadrant of the cylinder surface, means defining an elongated substantially continuous discharge orifice in the vessel, the vessel being formed and oriented to contain ink to a level substantially above the level of the orifice to produce a pressure head at the orifice and afford essentially gravity discharge of ink through the orifice, means mounting the vessel in a position locating the orifice in proximity to the plate cylinder periphery for application to the cylinder surface of the ink discharged through the orifice, and means for supplying ink to the vessel to maintain the pressure head therein as ink is discharged through the orifice and applied to the cylinder.
 2. An ink applicator according to claim 1 further comprising ink control means on the vessel downstream from the orifice, relative to the direction of rotation of the cylinder, and including an element spaced from the cylinder surface to define a clearance gap for controlling the thickness of the ink coating picked up on the cylinder surface.
 3. An applicator according to claim 2 wherein the vessel orifice is defined by elongated closely spaced parallel members on the vessel, the downstream member, relative to the direction of rotation of the cylinder, constituting the said ink control means.
 4. An applicator according to claim 1 further comprising a member on the vessel defining a surface upstream of the orifice, relative to the direction of rotation of the cylinder, and in proximity to the cylinder surface and supporting a band of ink of substantial width in contact with the cylinder surface.
 5. An ink applicator according to claim 4 wherein the end of the surface-defining member remote from the orifice defines a clearance gap with the cylinder surface over which ink discharged from the orifice in an amount in excess of the amount picked up on the cylinder overflows.
 6. An ink applicator according to claim 1 wherein the mounting means includes pivot members on the vessel pivotably carried by frame elements on the press.
 7. An ink applicator according to claim 6 further comprising spring means associated with the vessel for pivoting the vessel in a direction about the pivot mounting to urge the vessel orifice toward the cylinder surface and adjustable stop means for resisting pivotal movement of the vessel at the urging of the spring means and positioning the vessel with the orifice lOcated in predetermined spaced relation to the cylinder surface.
 8. An ink applicator according to claim 7 further comprising an operating lever located externally of a frame of the press and coupled to the vessel to afford pivotal movement of the vessel in a direction against the urging of the spring means.
 9. An ink applicator according to claim 1 wherein the ink supply mounting means affords setting the ink supply in adjusted positions relative to any of a plurality of different sized plate cylinders.
 10. An ink applicator according to claim 1 wherein the ink supply means includes a conduit extending through the vessel and having a plurality of outlet openings therein communicating the conduit with the vessel.
 11. An ink applicator according to claim 10 wherein the conduit is located in the region of the ink level in the vessel, and the openings are located in the conduit in positions to direct ink generally toward the discharge orifice to provide a velocity head supplementing the static head for discharging ink through the vessel orifice.
 12. An ink applicator according to claim 7 wherein the ink supply means includes a conduit extending entirely through the vessel and having plurality of spaced openings communicating the conduit with the vessel, the conduit including portions extending longitudinally from the vessel and pivotably coupled to frame elements of the press, the extension portions of the conduit being the pivot members by which the vessel is mounted on the press frame.
 13. An ink applicator according to claim 1 wherein the ink supply means includes an elongated ink supply conduit, the conduit being of a length substantially less than the length of the vessel and having a multiplicity of spaced-apart openings along its length for discharging ink into the vessel and being open at both ends to receive ink at one end and discharge ink into the vessel at the other end, and means coupled to the said one end to supply ink under pressure to the supply conduit.
 14. An ink applicator according to claim 13 wherein the said discharge end of the conduit is a nozzle.
 15. An ink applicator according to claim 13 wherein at least some of the openings in the conduit have deflector elements projecting into the conduit passage from generally the downstream edges of the openings, relative to the direction of flow of ink through the conduit, whereby ink flowing through the conduit impinges on the deflector element and is deflected thereby out through the associated opening into the vessel.
 16. An ink applicator according to claim 13 wherein the means for connecting the conduit to the ink supply includes a conical seat mounted on the vessel, a flared flange on the conduit matching the conical seat and means at a location spaced from the supply end of the conduit for securing the conduit to the vessel and for urging the flange of the conduit into seated and sealed relation on the seat.
 17. An ink applicator according to claim 16 wherein the means for securing the conduit to the vessel includes members having coacting angularly-related surfaces that provide a wedging action to urge the conduit into seated and sealed relation on the seat.
 18. An ink applicator according to claim 1 wherein the lower wall includes first and second sections, the second section being disposed adjacent the orifice and extending substantially the entire length of the vessel, and means reasonably connecting the second section to the first section, whereby the second section may be readily removed for cleaning out the vessel.
 19. An ink applicator according to claim 18 wherein the second section of the lower wall is hinged to the first section.
 20. An ink applicator according to claim 1 wherein the vessel has a portion at a level below the orifice and constituting the lowest portion of the vessel, and further comprising at least one drain port in the said lowest portion through which the ink in the vessel may drain out upon press shutdown.
 21. An ink applicator accordIng to claim 1 wherein the vessel further includes an opening above the ink level and generally at the uppermost ends of the upper and lower vessel walls, and further comprising ink capturing means for capturing ink expelled from the cylinder surface after ink application from the orifice and conducting it into the vessel through the opening.
 22. An ink applicator according to claim 1 wherein the vessel further includes an opening above the level of ink, and further comprising ink capturing means for capturing ink expelled from the cylinder surface after ink application from the orifice and conducting it into the vessel through the opening.
 23. An ink applicator according to claim 1 wherein the vessel orifice has a longitudinal dimension less than the longitudinal dimension of the cylinder surface, the vessel being positioned such that the ends of the orifice are spaced inwardly from the ends of the cylinder to leave marginal bands at the ends of the cylinder surface to which no ink is directly applied from the orifice, thereby to reduce ink leakage from the ends of the cylinder surface.
 24. An ink applicator for applying ink to the plate cylinder of a gravure press or the like, the press including a doctor blade to wipe ink from the cylinder surface and leave ink only in a recessed image formed thereon, comprising a vessel including spaced upper and lower walls curved generally to conform to the curvature of the cylinder surface and of a length such as to extend substantially coextensively lengthwise of the cylinder, the vessel occupying a space adjacent generally a lower quadrant of the cylinder, means defining an elongated substantially continuous outlet orifice adjacent generally the lowermost end of the vessel and facing upwardly in proximity to the cylinder surface, the vessel being adapted to contain ink to a level substantially above the level of the orifice thereby to produce a pressure head at the orifice and afford gravity discharge of ink through the orifice, means defining an opening in the vessel above the ink level, an ink control element on the vessel downstream of the discharge orifice, relative to the direction of rotation of the cylinder, and in closely spaced relation to the cylinder surface and defining a clearance gap controlling the thickness of the ink coating applied to the cylinder, means for supplying ink to the vessel to maintain the pressure head therein as ink is discharged through the orifice and applied to the cylinder, and means for mounting the vessel in a position adjustably locating the ink control element in predetermined spaced relation from the cylinder periphery for application to the cylinder surface of an ink coating of predetermined thickness.
 25. An applicator according to claim 24 further comprising a member on the vessel defining a surface upstream of the orifice, relative to the direction of rotation of the vessel, in proximity to the cylinder surface for supporting a band of ink discharging from the orifice of substantial width in contact with the cylinder surface.
 26. An ink applicator according to claim 25 wherein the end of the surface-defining member remote from the orifice defines a clearance gap with the cylinder surface over which ink discharged from the orifice in an amount in excess of the amount picked up on the cylinder overflows.
 27. An ink applicator according to claim 24 wherein the ink supply includes a conduit extending through the vessel and having a plurality of openings communicating it with the vessel, the openings located on the conduit in positions to direct ink in a direction generally toward the vessel orifice.
 28. An applicator according to claim 24 wherein the orifice has a longitudinal dimension less than the longitudinal dimension of the cylinder surface, the vessel being positioned so that the ends of the orifice are spaced from the ends of the cylinder surface to leave marginal bands on the ends of the cylinder surface to which no ink is directly applied from the orifice. 